AN ANALYTICAL TECHNIQUE FOR MEASURING RELATIVE TIE-MOLECULE CONCENTRATION IN POLYETHYLENE
AN ANALYTICAL TECHNIQUE FOR MEASURING RELATIVE TIE-MOLECULE CONCENTRATION IN POLYETHYLENE
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DOI：
10.1002/polb.1991.090290902
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发表时间：
1991-08-01
影响因子：
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通讯作者：
ISHIKAWA, N
中科院分区：
文献类型：
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作者：
LUSTIGER, A;ISHIKAWA, N
虽然长期以来对结晶域的考虑一直主导着理解半结晶聚合物特性的研究，但只有通过开发相应的分析工具来表征非晶区，才能对这些材料中的裂纹扩展有令人满意的理解。 由于这些材料中的缓慢稳定裂纹优先在结晶片层之间形成，因此连接分子（桥接结晶片层的无定形链）的作用在这方面特别重要。 不幸的是，没有现成的方法可用于定量评估连接分子。 通过聚乙烯薄膜的变形和随后的氯化，证明红外二色性可用于确定相对束缚分子浓度。 使用这种技术，人们可以先验地预测一系列具有可比密度但分子量或共聚单体分布变化很大的树脂表现出更好的抗裂性。
While consideration of the crystalline domains have long dominated research in understanding the properties of semicrystalline polymers, a satisfactory understanding of crack growth in these materials can only be realized by developing corresponding analytical tools to characterize the amorphous region. Since slow stable cracks in these materials preferentially form between crystalline lamellae, the role of tie molecules-the amorphous chains that bridge crystalline lamellae-are particularly important in this regard. Unfortunately, there is no method readily available for quantitative assessment of tie molecules. Through deformation and subsequent chlorination of polyethylene films, it is demonstrated that infrared dichroism can be used to determine relative tie-molecule concentration. Using this technique, one can a priori predict which resin in a series having comparable densities but widely varying molecular weights or comonomer distributions exhibits better crack resistance.